I will have an inch gap between the upper and lower row of sinks. This is part design and part to help inject fresh air into the second row of sinks. I have read that as the height of the sink increases the efficiency decreases, so hoping this helps a little. Rough layout of what would be each side of each monoblock.

I will cut off a little of each side of each sink to keep consistent look and will use half of another heatsink on each row to get 19" of consistent length, that's why I ordered 38 pieces.

Now on to cutting the tops, bottoms, fronts and backs out of 1/8" aluminum plate.

The heatsinks I purchased have smooth outside side fins and the internal fins are serrated. So at each splice I cut the smooth sided fins off, and in the correct location to maintain even fin spacing for the entire length of each section of heat sink.

Here is all the heatsink laid out (business card for reference). Pretty massive and to think this is all going to be so hot you can only touch for a few seconds? Almost makes you want to rethink this!

Based on the heatsink used in each DIY 5U chassis I have about 50% more square inches. Should be good to run up close to 150 watts?

Looking at your design, and the transformer you are planning to use. You will start to understand why I decided to split the monoblock into 2 chassis.
What you have drawn there with the trafo and all those heatsinks per monoblock, you will need a forklift to move that amp.

Also, since you want to try and bias that amp to 150W, you need a lot of air circulation not only on the outside, but also the inside as well. Note that the trafo will generate heat on its own too. Be careful with internal temperature. With that layout, I doubt you will hit 150W without the sinks surpassing 55 - 60C or above 25-30C above ambient, unless you want to store your amps outside in the winter

Since you decided to up the caps to 448kuF per, you are definitely going to need a slow charge circuit on top of the soft start. If you don't, your turn on spike will be in excess of 60A, and it won't lower to under 10A for quite a number of cycles. This will blow your house fuse and other components in the amp. The Soft start will NOT be enough. You may want to follow a few of the threads on the power supply section. There are a number of designs that would work for you. I used a very simple RC constant timer , but BigE and a number of others are discussing the use of a 555 timer which although more complicated, perhaps more suited.

Looking at your design, and the transformer you are planning to use. You will start to understand why I decided to split the monoblock into 2 chassis.
What you have drawn there with the trafo and all those heatsinks per monoblock, you will need a forklift to move that amp.

Also, since you want to try and bias that amp to 150W, you need a lot of air circulation not only on the outside, but also the inside as well. Note that the trafo will generate heat on its own too. Be careful with internal temperature. With that layout, I doubt you will hit 150W without the sinks surpassing 55 - 60C or above 25-30C above ambient, unless you want to store your amps outside in the winter

Since you decided to up the caps to 448kuF per, you are definitely going to need a slow charge circuit on top of the soft start. If you don't, your turn on spike will be in excess of 60A, and it won't lower to under 10A for quite a number of cycles. This will blow your house fuse and other components in the amp. The Soft start will NOT be enough. You may want to follow a few of the threads on the power supply section. There are a number of designs that would work for you. I used a very simple RC constant timer , but BigE and a number of others are discussing the use of a 555 timer which although more complicated, perhaps more suited.

Andrew, thanks for commenting on my plans so far. I hope you don't mind if I pick your brain from time to time? What you have done is the closest build to what I had in mind. My exterior design might hold me back from getting to a full 150w. I do have two 13" subs with 500w each internal amps, so I already have some punch available. But if your going to build something it doesn't take that much extra to have extra, right?

I understand that I'm going to have to add some additional complexity for slow and soft start systems.

Where/what did you get matched mosfets?

I read some of your posts on Canuck. What positions did you you use nudies? That's what I used in my preamp for all the resistors in the signal path. The plan calls for .5w and the nudies are rated at .4, any issues?

Depending on which mosfets, I got the FQA's from Buzzforb here on a GB.
If you want toshiba's then zhoufang, via his ebay account these days, if you can get a hold of him...

I used the TX2575's in R1 and R13 (and its corresponding mirrors)

Thanks for the quick reply.

You used the FQA's, any reason not the Toshiba's?

Have you started building the second pair? Any changes contemplated?

Since I'm a "DIY in training" can you confirm for me (and others who might know less than me) these locations for the nudes? I'm assuming you used 47r instead of the 47r5's? I have a pair of 1k2 nudes left from another project, do you think these will be ok in place of the 1k for position R1?

There is no reason not to use the toshibas. I just wanted to try the FQA's. The second one I'm building I'll be using the Toshiba's, then I'll get to race them
I have enough to do swaps, depending on which one sounds better

Yes the locations you pointed out is where I decided to use the TX2575's.
I used 47r5 as per schematic.
I don't know enough about circuit design to say that a 1k2 would work just as well as the specified 1k. Perhaps someone else on the forum may be able to tell you what a higher resistance would do....

Note that there are a lot of combinations of resistor brands etc that you can use to customize the sound. Since some here may say that its bogus, I won't advocate to use certain brands over another... but in my experience with the F5, I hear differences. The nudes aren't the only resistors I changed from even the GB premium set.